| 莱河矿(Fe0.52+Fe1.03+SiO4)的超结构 |
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| 引用本文： | 沈步明,玉田攻,北村雅夫,森本信男.莱河矿(Fe0.52+Fe1.03+SiO4)的超结构[J].地质科学,1982,0(3):341-342. |
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| 作者姓名： | 沈步明 玉田攻 北村雅夫 森本信男 |
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| 作者单位： | 1. 中国科学院地质研究所;2. 日本京都大学 |
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| 摘 要： | 莱河矿于1976年在中国辽宁省的磁铁矿床中首次被发现,许多人对它进行过研究。该矿物为黑色、不透明,化学式为Fe0.582+Fe1.03+Mg0.03Si0.96O4,虽然它的晶体结构近似于橄榄石,但已确定为单斜晶系,空间群为P21/b。本文作者利用X射线、电子探针、高分解能透过电子显微镜对该矿物进行了系统的研究,发现它具有假双晶、超结构和显微条纹结构。
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| 关 键 词： | , |
| 收稿时间： | 1982-04-18 |
| 修稿时间： | 1982-04-18; |
SUPERSTRUCTURE OF LAIHUNITE (Fe0.52+Fe1.03+SiO4) |
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| Shen Buming,Osamu Tarnada,Masao Kitamura,Nobuo Morimoto.SUPERSTRUCTURE OF LAIHUNITE (Fe0.52+Fe1.03+SiO4)[J].Chinese Journal of Geology,1982,0(3):341-342. |
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| Authors: | Shen Buming Osamu Tarnada Masao Kitamura Nobuo Morimoto |
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| Institution: | 1. Institute of Geology Academica Sinica, Beijing, China;2. Kyoto University, Kyoto, Japan |
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| Abstract: | The crystal structure and textures of laihunite have been studied by X-ray diffraction,EPMA and high resolution electron microscopy.Laihunite always appears as the form of pseudo-twin in the composition plane (001).It shows fine lamellar texures of two distinct phases in the electron micrographs,Submicroscopic lamellar textures of magnetite in laihunite,indicate that ‘laihunite’ is a mixture of laihunite proper and magnetite,and was derived from oxidation of fayalite.The crystal structure of laihunite is & superstructure of distorted olivine-type structure.The appearance of the satellite reflection along the c*-axis indicates the super-lattice structures of 2c and 3c.The lattice constants of supercell are a=4.805(2),b=10.189(9),c=5.801(3) X n,and a -91.0(2),where n’s is equal to 2 or 3.The superstructure of 3c type was determined by the 3-dimensional 2707 reflections from a twinned crystal on the basis of space group P21/b.The final and weighted R converges to 0.141 and 0.094 respectively.The superstruture (3C) result from the ordered arrangement of Fe2+,Fe3+ and vacancy.In orther words,the positions at (1/2,1/2 1/2) of M(l) sites are filled only half with Fe2+.Whereas the positions at (1/2 1/2 1/6) of M(l) sites are entirely vacant.The positions of Fe2+ and Fe3+ are slightly shifted as compared with fayalite. |
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| Keywords: | , |
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